1. Field
Example embodiments of the inventive concepts relate to semiconductors, and more particularly, to semiconductor memory devices.
2. Description of the Related Art
Integration density of semiconductor memory devices may be an important factor for determining the price of a product. In the case of typical two-dimensional or planar semiconductor memory devices, integration density is mainly determined by the area occupied by a unit memory cell, thereby being largely affected by the advancement of fine pattern formation technology. Although the integration density of two-dimensional semiconductor memory devices is increasing, ultra-expensive equipment needed to form a fine patterns is restrictive. Therefore, vertical transistor technology has been suggested for realizing high integration density semiconductor memory devices.